Knitting machine

ABSTRACT

A cam for a circular knitting machine has at least one cam groove formed in a cam surface to receive and guide a foot of a stitch-forming tool with which the cam is intended to operate. Additional recesses are formed in the cam surface to reduce the striking surface between the cam surface and a shank of the stitch-forming tool.

CROSS-REFERENCE TO A RELATED APPLICATION

The invention described and claimed hereinbelow is also described inGerman Priority Document DE 10 2013 208066.2, filed on May 2, 2013. TheGerman Priority Document, the subject matter of which is incorporatedherein by reference, provides the basis for a claim of priority ofinvention under 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The present invention relates to a cam for a circular knitting machinewith at least one cam groove formed in the cam surface to receive andguide a foot configured on a stitch-forming tool.

Cams of circular knitting machines are not only for raising thestitch-forming tools for the stitching-forming operation. Cams ofcircular knitting machines also hold the stitch-forming tools in theirposition with their surface. In this way, for example, the cams preventthe cylinder needles of a circular knitting machine from being swungradially outwards by the centrifugal forces that arise during rotationof the cylinder. In plain circular knitting machines, the sinker camsprevent the down sinkers from tilting as a result of the action of forceof the stitches.

In all these cases, the stitch-forming tools are pressed against the camsurfaces. Since the stitch-forming tools move relative to the cams,friction forces thus arise that lead to a premature wear of thestitch-forming tools in particular. Moreover, the friction causes aconsiderable development of heat and demands a higher energy requirementof the drive of the machine. Therefore, the cams are lubricated in orderto keep the friction energy as low as possible.

SUMMARY OF THE INVENTION

The present invention overcomes the shortcomings of known arts, such asthose mentioned above.

To that end, the present invention provides cams in which the frictionbetween their surface and stitch-forming tools with which the cam orknitting machine are intended to be used is reduced.

In an embodiment, the invention provides a cam fora circular knittingmachine with at least one cam groove formed in its surface to receiveand guide a foot configured on a stitch-forming tool. The cam groove ischaracterised in that additional recesses are formed in the cam surfaceto reduce the striking surface between the cam surface and the shank ofthe stitch-forming tools.

In this case, the stitch-forming tools that are guided in at least onecam groove are any of the group consisting of needles, control sinkers,down sinkers, swivel sinkers, spring sinkers, spring pins, intermediatepins and jack selectors, for example, without limitation.

The recesses in the cam surface not only cause the abutment surfacesbetween the cams and the stitch-forming tools to be reduced and thus thefriction to be reduced, but also cause the flow of the lubricant on thecam surface to slow down. The oil collects in the recesses, which thusform oil reservoirs for an improved lubrication. As a result, thefriction between the stitch-forming tools and the cam surface is furtherreduced, and thus less wear and less heating up of the stitch-formingtools occur. Moreover, the need for lubricant is reduced with theinvention.

For that matter, the inventive cams are individualised in amanufacturer-specific manner and distinguished more easily from copiesby the type of recesses.

In a cam embodiment, the cam recesses are channels or grooves, whichextend in the running direction of the stitch-forming tools with whichthe cam or knitting machine are intended to be used. These recesses canslow down the flow of the lubricant on the cam surface from top tobottom over the entire width of the cam. In this case, the channels orgrooves preferably run parallel to the at least one cam groove, as aresult of which the cam surface is provided very uniformly withfriction-reducing recesses.

In an embodiment, the channels or grooves can extend in a star shapefrom an oil nozzle outlet. The oil is transported upwards from below inthese grooves and the oil consumption can thus be reduced.

Intersecting channels or grooves also can be used to enable the oil tobe evenly distributed. However, other configurations of the recesses arealso usable, e.g., such as cylindrical, arrow-shaped or trough-shapedrecesses arranged in a uniform grid, without limitation.

In this case, the depth of the channels or grooves can decrease orotherwise vary in the running direction of the stitch-forming tools. Asa result of this measure, a pumping action is generated for the oilcollecting in the recesses and the lubrication effect can thus beimproved.

A further reduction in friction between the cam and the stitch-formingtools is achieved in that the cam surface between the recesses is convexat least in regions. This results in merely punctiform abutment pointsbetween the stitch-forming tools and the cams. Oil can collect in therecesses.

It also is possible to provide multiple recesses of different shapes ina cam.

In the cam embodiment provided with grooves or channels running parallelto the cam groove, a stitch-forming tool is used that is preferablyprovided with a flat projection on its shank that is inserted into oneof the grooves or channels. The projection preferably runs in the grooveor channel without touching. A cam without the groove to fit theprojection cannot then be operated with this stitch-forming tool.Copying of cams can thus be made more difficult.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparentfrom the description of exemplary embodiments that follows, withreference to the attached

Figs, wherein:

FIG. 1 presents a perspective view of a first cam;

FIG. 2 presents a perspective view of a second cam;

FIG. 3 presents a perspective view of a third cam;

FIG. 4 a presents a perspective view of a fourth cam;

FIG. 4 b presents a perspective view of a fifth cam;

FIG. 5 a presents a perspective view of a sixth cam;

FIG. 5 b presents a view from above onto the cam depicted in FIG. 5 a;

FIG. 6 presents a perspective view of a seventh cam;

FIG. 7 presents a perspective view of an eighth cam;

FIG. 8 presents a perspective view of a ninth cam;

FIG. 9 a presents a perspective view of a further production variant ofthe cam depicted in FIG. 3;

FIG. 9 b presents a perspective view of a further production variant ofthe cam depicted in FIG. 3;

FIG. 9 c presents a perspective view of a further production variant ofthe cam depicted in FIG. 3; and

FIG. 10 presents a perspective view of the cam depicted in FIG. 1 with astitch-forming tool.

DETAILED DESCRIPTION OF THE INVENTION

The following is a detailed description of example embodiments of theinvention depicted in the accompanying drawings. The example embodimentsare presented in such detail as to clearly communicate the invention andare designed to make such embodiments obvious to a person of ordinaryskill in the art. However, the amount of detail offered is not intendedto limit the anticipated variations of embodiments; on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the present invention, as definedby the appended claims.

FIG. 1 presents a cam 10 of a circular knitting machine (not furthershown) to include a cam groove 11 for guiding a foot 12 of astitch-forming tool 13, one embodiment of which is shown in FIG. 10. Thecourse of the cam groove 11 depends on the raising arid return movementsthat the stitch-forming tool 13 is configured to perform. Two recesses14, 15 in the form of broad shallow grooves are moulded into the surface16 of the cam 10 parallel to the cam groove 11. The two recesses 14, 15serve to reduce the striking surface between the surface 16 of the cam10 and the shank of the stitch-forming tool 13 (FIG. 10). Moreover, thetwo recesses 14, 15 serve to slow down the flow-off of lubricant on thesurface 16 of the cam 11 in the direction of arrow 18. The lubricant ispartially collected in the recesses 14, 15, which thus form a lubricantreservoir. The depth of the recesses 14, 15 can vary in the runningdirection, the direction of arrow 19, of the stitch-forming tools 13 inthis case.

FIG. 2 shows a second exemplary embodiment of a cam 20, which besidesthe cam groove 21 is provided with channel-shaped recesses 22 runningparallel thereto in its surface 26. Like the groove-shaped recesses 14,15 of the cam 10 (FIG. 1), the recesses 22 of cam 20 also ensure areduction of the contact surface between a stitch-forming tool 13 andthe surface 26, as shown. At the same time, lubricant running downwardson the surface 26 is partially collected over the entire width of thecam 20. The resulting friction between the stitch-forming tools 13 andthe cam 20 is thereby reduced, the lubricant requirement decreased andthe energy requirement of the drive of the circular knitting machinelowered.

In contrast to the configurations of FIGS. 1 and 2, the cam 30 shown inFIG. 3 has a plurality of blind hole-type recesses 32 arranged in auniform grid and a groove 31. These blind hole-type recesses 32 aresuitable for reducing the striking surface between the stitch-formingtools 13 and the cam 30 and collect lubricant flow-off.

FIGS. 4 a and 4 b show respective cams 40 and 45, each with respectivearrow-shaped recesses 41, 42. Recesses 41 extend in the cam runningdirection 43 and recesses 42 extend in the opposite direction. Recesses41, 42 form an oil reservoir. Moreover, recesses 41, 42 aresubstantially conical in shape so that a kind of pumping effect isachieved for the oil with recesses 41. The recesses 42 directed in theopposite direction serve as receiver for excess oil. A trough shape alsomay be selected for recesses 41, 42, instead of an arrow or conicalshape.

FIGS. 5 a and 5 b show a cam 50 (FIG. 5 b presents a view from aboveonto the cam depicted in FIG. 5 a), in which the recesses 51 areconfigured such that hump-shaped raised areas 52 provide the contactsurfaces with the stitch-forming tools. As a result, friction betweenthe stitch-forming tools and the cam surface only occurs at punctiformareas. In order to assure a uniform guidance of the stitch-formingtools, the hump-shaped raised areas 52 also may be staggered relative toone another.

The cam 60 is shown in FIG. 6 to have grooves 62 as recesses that extendin a star shape from oil inlets or outlets 61. All the grooves 62 extendupwards in the running direction 63 of the cam 60. As a result, the oilis transported from the bottom upwards in the grooves and the oilconsumption can thus be reduced. In the opposite running direction ofthe cam 60 the grooves 62 are used for oil flow out of the cam 60.

FIG. 7 shows a further cam 70 with horizontally running groove-shapedrecesses 71. Cam 70 is distinguished, as shown, and by an extremelysimple manufacture.

In contrast, FIG. 8 shows a cam 80 with intersecting rectilinear grooves81 as recesses. This course of the grooves 81 enables the oil to beevenly distributed over the cam surface.

FIG. 9 c shows a cam 30′, which is a variant of the cam 30 depicted inFIG. 3. In contrast to cam 30, cam 30′ is not produced in one piece, butfrom a base plate 35 (FIG. 9 a) and two shell parts 36 a, 36 b (FIG. 9b). A cam groove 31 is formed in the base plate 35 for the foot of astitch-forming tool (not shown). The two shell parts 36 a, 36 b areprovided with blind hole-like recesses 32 and are fastened to the baseplate 35 in such a manner that the cam groove 31 is exposed between theshell parts 36 a, b. In the case of thicker shell parts 36 a, 36 b, thecam groove 31 also may be configured exclusively between the shell parts36 a, 36 b or, in a single-part shell part. Therefore, different shellparts 36 a, 36 b can be arranged on a uniform base plate 35 and thecosts for production of the cam 30 are reduced.

Recesses 14, 16, 22, 32, 41, 42, 51, 62, 71, 81, included in cams 10 to80, also may be used to individualise the cams of a manufacturer andrender it more difficult for unauthorised copies to be fabricated. Thisprotection against copying is further increased if the stitch-formingtools 13 are matched individually to the cam, for example, cam 10 or itsrecesses 14, 15, as made clear in FIG. 10. Therein, cam 10 with therecesses 14, 15 together with a stitch-forming tool 13 is shown onceagain. As usual, the stitch-forming tool 13 has a foot 12, which isguided in the cam groove 11 and thus assures the raising and returnmovements of the stitch-forming tool 13. In addition, the stitch-formingtool 13 is provided with a projection 17, which engages into thegroove-shaped recess 14 and moves along this in a friction-free mannerwhen the foot 12 is moved along the cam groove.

The stitch-forming tool 13 is thus matched exactly to the cam 10 andcannot be used together with other cams, e.g., the cams 20, 30 orconventional cams without recesses in the surface.

As will be evident to persons skilled in the art, the foregoing detaileddescription and figures are presented as examples of the invention, andthat variations are contemplated that do not depart from the fair scopeof the teachings and descriptions set forth in this disclosure. Theforegoing is not intended to limit what has been invented, except to theextent that the following claims so limit that.

What is claimed is:
 1. A cam fore circular knitting machine, comprising:at least one cam groove formed in a cam surface to receive and guide afoot configured on a stitch-forming tool, with which stitch-forming toolthe cam is intended to operate; and one or more recesses formed in thecam surface to reduce a striking surface between the cam surface and ashank of the stitch-forming tool.
 2. The cam according to claim 1,wherein the one or more recesses embody channels or grooves that extendin a running direction of a stitch-forming tool with which the cam isintended to operate.
 3. The cam according to claim 2, wherein thechannels or grooves extend parallel to the at least one cam groove. 4.The cam according to claim 1, wherein the cam further comprises an oiloutlet nozzle and wherein one or more recesses are channels or groovesthat extend in a star shape from the cam oil nozzle.
 5. The camaccording to claim 1, wherein the one or more recesses are intersectinggrooves or channels.
 6. The cam according to claim 1 wherein the one ormore recesses are cylindrical, arrow-shaped or trough-shaped inconfiguration.
 7. The cam according to claim 1, wherein the depth of theone or more recesses varies in a running direction of stitch-formingtools with which the cam is intended to operate.
 8. The cam according toclaim 1, wherein the cam surface between the one or more recesses isconvex at least in regions.
 9. The cam according to claim 1, wherein thecam is formed by a base plate, on which at least one shell part formingthe cam surface is arranged.
 10. The cam according to claim 1, whereinone or more stitch-forming tools which are intended to be guided in theat least one cam groove are any of the group of stitch-forming toolsconsisting of needles, control sinkers, down sinkers, swivel sinkers,spring sinkers, spring pins, intermediate pins and jack selectors. 11.Stitch-forming tool configured for operation with a cam for a circularknitting machine, the stitch-fitting tool comprising a shank having afoot and a flat projection; wherein the cam comprises at least one camgroove formed in a cam surface to receive and guide the foot of thestitch-forming tool; and one or more recesses formed in the cam surfaceto reduce a striking surface between the cam surface and the shank ofthe stitch-forming tool that embody channels or grooves that extend in arunning direction of the stitch-forming tool; wherein the channels orgrooves extend parallel to the at least one cam groove and wherein theflat projection inserted into one of the grooves or channels.
 12. Thestitch-forming tool according to claim 11, wherein the cam is formed bya base plate, on which at least one shell part forming the cam surfaceis arranged and wherein the projection runs in the groove or channelwithout touching.